U.S. patent application number 15/084718 was filed with the patent office on 2016-10-27 for ink jet recording method.
The applicant listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Fumihiro Goto, Koichiro Nakazawa, Eisuke Nishitani, Takumi Otani, Kanako Soma, Keiichirou Takeuchi.
Application Number | 20160311235 15/084718 |
Document ID | / |
Family ID | 55650002 |
Filed Date | 2016-10-27 |
United States Patent
Application |
20160311235 |
Kind Code |
A1 |
Takeuchi; Keiichirou ; et
al. |
October 27, 2016 |
INK JET RECORDING METHOD
Abstract
An ink jet recording method in which an image is formed by
applying onto a recording medium a reaction liquid, an aqueous
pigment ink containing an anionic polymer aggregatable by the
reaction liquid and a resin-containing aqueous liquid containing an
anionic polymer aggregatable by the reaction liquid to form an
image, the method including the steps of applying the reaction
liquid to the recording medium; applying the aqueous pigment ink to
a surface of the recording medium to which the reaction liquid is
applied by an ink jet method to form an image; and applying the
resin-containing aqueous liquid to the image formed on the
recording medium by the ink jet method. The surface tension of the
resin-containing aqueous liquid is higher than the surface tension
of the aqueous pigment ink.
Inventors: |
Takeuchi; Keiichirou;
(Komae-shi, JP) ; Nakazawa; Koichiro;
(Machida-shi, JP) ; Goto; Fumihiro; (Kawasaki-shi,
JP) ; Nishitani; Eisuke; (Tokyo, JP) ; Soma;
Kanako; (Yokohama-shi, JP) ; Otani; Takumi;
(Kawasaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
|
JP |
|
|
Family ID: |
55650002 |
Appl. No.: |
15/084718 |
Filed: |
March 30, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J 2002/012 20130101;
C09D 125/14 20130101; C09D 133/06 20130101; B41J 11/0015 20130101;
C09D 11/30 20130101; B41J 2/01 20130101; B41M 5/0017 20130101; B41M
5/0256 20130101 |
International
Class: |
B41J 11/00 20060101
B41J011/00; C09D 133/06 20060101 C09D133/06; C09D 125/14 20060101
C09D125/14; B41J 2/01 20060101 B41J002/01; C09D 11/30 20060101
C09D011/30 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2015 |
JP |
2015-089105 |
Claims
1. An ink jet recording method in which an image is formed by
applying onto a recording medium a reaction liquid, an aqueous
pigment ink containing an anionic polymer aggregatable by the
reaction liquid and a resin-containing aqueous liquid containing an
anionic polymer aggregatable by the reaction liquid to form an
image, the method comprising the steps of: applying the reaction
liquid to the recording medium; applying the aqueous pigment ink to
a surface of the recording medium to which the reaction liquid is
applied by an ink jet method to form an image; and applying the
resin-containing aqueous liquid to the image formed on the
recording medium by the ink jet method, wherein a surface tension
of the resin-containing aqueous liquid is higher than a surface
tension of the aqueous pigment ink.
2. The ink jet recording method according to claim 1, wherein the
surface tension of the resin-containing aqueous liquid is 3 mN/m or
more higher than the surface tension of the aqueous pigment
ink.
3. The ink jet recording method according to claim 1, wherein the
surface tension of the resin-containing aqueous liquid is 5 mN/m or
more higher than the surface tension of the aqueous pigment
ink.
4. The ink jet recording method according to claim 1, wherein the
recording medium is cast-coated paper.
5. The ink jet recording method according to claim 1, wherein the
anionic polymer is a water-soluble resin having a weight-average
molecular weight of 5,000 or more and 10,000 or less.
6. The ink jet recording method according to claim 1, further
comprising a step of removing water from the image formed on the
recording medium after the step of applying the resin-containing
aqueous liquid.
7. An ink jet recording method in which an image is formed by
applying onto a first recording medium a reaction liquid, an
aqueous pigment ink containing an anionic polymer aggregatable by
the reaction liquid and a resin-containing aqueous liquid
containing an anionic polymer aggregatable by the reaction liquid
followed by transferring the intermediate image formed on the first
recording medium to a second recording medium, the method
comprising the steps of: applying the reaction liquid to the first
recording medium; applying the aqueous pigment ink to a surface of
the first recording medium to which the reaction liquid is applied
by an ink jet method to form an image; and applying the
resin-containing aqueous liquid to the image formed on the first
recording medium by the ink jet method, wherein a surface tension
of the resin-containing aqueous liquid is higher than a surface
tension of the aqueous pigment ink.
8. The ink jet recording method according to claim 7, wherein the
surface tension of the resin-containing aqueous liquid is 3 mN/m or
more higher than the surface tension of the aqueous pigment
ink.
9. The ink jet recording method according to claim 7, wherein the
surface tension of the resin-containing aqueous liquid is 5 mN/m or
more higher than the surface tension of the aqueous pigment
ink.
10. The ink jet recording method according to claim 7, wherein the
first recording medium is a transfer member, and the transfer
member has a support member and a surface layer member on the
support member.
11. The ink jet recording method according to claim 10, wherein the
surface layer member comprises a siloxane compound.
12. The ink jet recording method according to claim 7, wherein the
second recording medium is cast-coated paper.
13. The ink jet recording method according to claim 7, wherein the
anionic polymer comprises a water-soluble resin having a
weight-average molecular weight of 5,000 or more and 10,000 or
less.
14. The ink jet recording method according to claim 7, further
comprising a step of removing water from the intermediate image
formed on the first recording medium after the step of applying the
resin-containing aqueous liquid.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ink jet recording
method.
[0003] 2. Description of the Related Art
[0004] An ink jet recording apparatus has an ink ejection orifice
for ejecting an ink on a recording medium to form an image and can
record a high-definition image at a high speed.
[0005] In recent years, utilization of an ink jet recording
apparatus for commercial printing has also been widely
investigated. In the ink jet recording apparatus for commercial
printing, a pigment ink is generally used from the viewpoint of
weather resistance of a printed article. At that time, such an ink
is required to enable forming a good image even on a recording
medium which does not have an ink receiving layer for fixing a
pigment ink droplet impacted on a paper surface as in exclusive
paper for ink jet, such as normal printing paper.
[0006] As a method for meeting the above required performance,
there may be mentioned an image forming method in which a reaction
liquid is applied on to a recording surface of a recording medium
before the impact of an ink droplet to bring the ink droplet into
contact with the reaction liquid applied, thereby causing
aggregation of a component contained in an ink to fix the ink
droplet on the recording medium. According to this image forming
method, a good image from which image defects such as bleeding and
beading are inhibited can be formed.
[0007] On the other hand, in the ink jet recording apparatus for
commercial printing, it is attempted to provide such an added value
that an image with photographic image quality is formed on normal
printing paper. In order to achieve the photographic image quality
in a printed article, high-price exclusive paper for photography is
generally required. If the image with photographic image quality
can be formed on cheap printing paper, however, such an added value
that an image with photographic image quality can be formed at low
cost can be given to the ink jet recording apparatus.
[0008] The photographic image quality is required to have a high
gloss feeling and high gloss uniformity. On the exclusive paper for
ink jet, the high gloss feeling and the high gloss uniformity are
achieved by applying a transparent ink to an image formed with a
pigment ink.
[0009] Japanese Patent Application Laid-Open No. 2004-181803
discloses a method for improving the gloss uniformity of an image
by alleviating bumpy irregularities formed by impact dots of a
pigment ink formed as a projected portion on a surface of a
recording medium by applying a transparent liquid which contains a
resin and does not contain a colorant thereto.
[0010] In addition, Japanese Patent Application Laid-Open No.
2013-18127 discloses an ink jet recording method using a pigment
ink and a coating liquid applied later, in which the hydrophilicity
of a film forming resin particle contained in the coating liquid is
made higher than the hydrophilicity of a film forming resin
particle contained in the pigment ink. In Japanese Patent
Application Laid-Open No. 2013-18127, a combination of such pigment
ink and coating liquid accelerates the formation of a film by the
coating liquid on the surface of a pigment contained in an ink film
on a recording medium and also alleviates bumpy irregularities of
the film itself by the coating liquid, thereby realizing the high
gloss feeling and the high gloss uniformity.
SUMMARY OF THE INVENTION
[0011] According to an embodiment of the present invention, there
is provided an ink jet recording method in which an image is formed
by applying onto a recording medium a reaction liquid, an aqueous
pigment ink containing an anionic polymer aggregatable by the
reaction liquid and a resin-containing aqueous liquid containing an
anionic polymer aggregatable by the reaction liquid, the method
comprising the steps of:
applying the reaction liquid to the recording medium; applying the
aqueous pigment ink to a surface of the recording medium to which
the reaction liquid is applied by an ink jet method to form an
image; and applying the resin-containing aqueous liquid to the
image formed on the recording medium by the ink jet method, wherein
the surface tension of the resin-containing aqueous liquid is
higher than the surface tension of the aqueous pigment ink.
[0012] According to another embodiment of the present invention,
there is also provided an ink jet recording method in which an
image is formed by applying onto a first recording medium a
reaction liquid, an aqueous pigment ink containing an anionic
polymer aggregatable by the reaction liquid and a resin-containing
aqueous liquid containing an anionic polymer aggregatable by the
reaction liquid to form an intermediate image followed by
transferring the intermediate image formed on the first recording
medium to a second recording medium, the method comprising the
steps of:
applying the reaction liquid to the first recording medium;
applying the aqueous pigment ink to a surface of the first
recording medium to which the reaction liquid is applied by an ink
jet method to form an image; and applying the resin-containing
aqueous liquid to the image formed on the first recording medium by
the ink jet method, wherein the surface tension of the
resin-containing aqueous liquid is higher than the surface tension
of the aqueous pigment ink.
[0013] According to the present invention, there can be provided an
ink jet recording method which does not easily cause image cracking
and can form an image having high glossiness and gloss
uniformity.
[0014] Further features of the present invention will become
apparent from the following description of exemplary embodiments
with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates an example of a direct drawing type ink
jet image forming apparatus for carrying out the present
invention.
[0016] FIGS. 2A, 2B and 2C are drawings for explaining an estimated
mechanism of occurrence of image cracking.
[0017] FIG. 3 illustrates an example of a method for quantitatively
comparing an image cracking state.
[0018] FIG. 4 illustrates an example of a transfer type ink jet
image forming apparatus for carrying out the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0019] Preferred embodiments of the present invention will now be
described in detail in accordance with the accompanying
drawings.
[0020] According to an investigation by the present inventors, it
has been found that when an image formed on any one of various
kinks of printing paper, not exclusive paper for ink jet, by an ink
jet method is treated with a liquid which contains a resin for
improving glossiness of the image and does not contain a coloring
material like the methods disclosed in Japanese Patent Application
Laid-Open No. 2004-181803 and Japanese Patent Application Laid-Open
No. 2013-18127, "image cracking" which is cracking caused over the
whole image may occur in some cases. In particular, it has been
found that the image cracking may easily occur in some cases in the
case of the method disclosed in Japanese Patent Application
Laid-Open No. 2013-18127, in which the affinity of the resin
particle contained in the coating liquid for the pigment forming
the image on the recording medium is improved.
[0021] The present invention has been made while paying attention
to the above problem, and it is an object of the present invention
to provide an ink jet recording method which does not easily cause
image cracking and can form an image having high glossiness and
gloss uniformity.
[0022] Embodiments for carrying out the present invention will now
be described.
[0023] Ink Jet Recording Method
[0024] The ink jet recording method according to the present
invention will be described with reference to the schematic views
of the ink jet image forming apparatus illustrated in FIGS. 1 and
4.
[0025] As for examples of the ink jet recording method according to
the present invention, there are mentioned "direct drawing type ink
jet recording method" in which an ink and a liquid composition are
directly applied to a recording medium to record an image, and
"transfer type ink jet recording method" in which an ink and a
liquid composition are applied to a transfer member as a first
recording medium to form an intermediate image followed by
transferring the intermediate image to a second recording medium
such as paper to record an image. The respect ink jet recording
methods will now be described.
[0026] (1) Direct Drawing Type Ink Jet Recording Method
[0027] FIG. 1 schematically illustrates a direct drawing type ink
jet image forming apparatus. In FIG. 1, a recording medium 12 is
first fixed to a conveyance stage (also referred to as a sheet
fixing member) 11 to convey the recording medium in a direction of
the arrow. A number of suction holes are made in a surface of the
conveyance stage 11, on which the recording medium 12 is placed and
fixed, and so the recording medium 12 can be fixed when needed by
sucking it through these holes. A reaction liquid is applied to the
recording medium 12 conveyed in the direction of the arrow.
[0028] In the example illustrated, a roller type coating device 14
is provided for applying the reaction liquid to the recording
medium 12. This roller type coating device has a coating roller
system composed of a reaction liquid tank for storing the reaction
liquid 13, a coating roller for applying the reaction liquid to the
surface of the recording medium and a supply roller for supplying
the reaction liquid to the coating roller from the reaction liquid
tank. The reaction liquid 13 contains components respectively
causing aggregation of a component contained in a pigment ink and a
component contained in a resin-containing liquid. The apparatus
illustrated in FIG. 1 has liquid ejection heads 15 and 16 according
to an ink jet system, and the liquid ejection head 15 is used for
forming an image with the pigment ink, and the liquid ejection head
16 is used for applying the resin-containing liquid.
[0029] When the recording medium 12 to which the reaction liquid
has been applied reaches the position of the liquid ejection head
15 for ejecting the pigment ink, the pigment ink is ejected from
the liquid ejection head 15 to form an image. At that time, the
component contained in the pigment ink is aggregated by contact of
the reaction liquid applied in advance with the pigment ink to form
a coloring ink layer.
[0030] When the recording medium 12 further reaches the position of
the liquid ejection head 16, the resin-containing liquid is applied
on to the image formed in advance. The resin-containing liquid is
also aggregated by contact with the reaction liquid like the
pigment ink to form a resin layer containing no coloring material
on the image. In the case where drying is further required
thereafter, the recording medium 12 having the image is caused to
reach the position of a hot air drying device 17 to conduct hot air
drying.
[0031] When the resin layer containing no coloring material is
formed on the image after that image is formed with the pigment
ink, such an image cracking defect that the interior of the image
is cracked may occur in some cases according to application
conditions of the pigment ink and the resin-containing liquid. On
the contrary, the image forming method according to the present
invention has an effect to inhibit the image cracking because both
pigment ink and resin-containing liquid are aqueous, and the
surface tension of the aqueous resin-containing liquid is made
higher than the surface tension of the aqueous pigment ink.
[0032] Recording Medium
[0033] No particular limitation is imposed on the recording medium
used in the present invention. In order to form an image having
photographic image quality, it is favorable to achieve a high gloss
feeling for the image. Accordingly, for forming such an image
having photographic image quality, such a recording medium that the
smoothness of its image forming surface is good is desired. Coated
paper having a coating layer is favorable as a recording medium
capable of providing a recording surface having high smoothness,
and cast-coated paper having high smoothness is more favorable.
[0034] As examples of the coated paper, there may be mentioned coat
paper sheets such as art paper, high-quality coat paper and
medium-quality coat paper, light weight coat paper sheets such as
high-quality light weight coat paper and medium-quality light
weight coat paper, and coat paper sheets such as fine coated
printing paper. The coating weight of the coating layer of the
coated paper is about 40 g/m.sup.2 on both surfaces of the art
paper, about 20 g/m.sup.2 on both surfaces of the high-quality coat
paper and the medium-quality coat paper, about 15 g/m.sup.2 on both
surfaces of the high-quality light weight coat paper and the
medium-quality light weight coat paper, and 12 g/m.sup.2 or less on
both surfaces of the fine coated printing paper. Examples of the
art paper include TOKUBISHI ART (product of Mitsubishi Paper Mills
Co.) and SATIN KINFUJI (product of Oji Paper Co., Ltd.).
[0035] Examples of the coat paper include OK TOP COAT (product of
Oji Paper Co., Ltd.), AURORA COAT (product of Nippon Paper
industries Co., Ltd.) and RECYCLE COAT T-6 (product of Nippon Paper
industries Co., Ltd.), and examples of the light weight coat paper
include U-LITE (product of Nippon Paper industries Co., Ltd.), NEW
V-MATT (product of Mitsubishi Paper Mills), NEW AGE (product of Oji
Paper Co., Ltd.), RECYCLE MATT T-6 (product of Nippon Paper
industries Co., Ltd.) and PISM (product of Nippon Paper industries
Co., Ltd.). Examples of the fine coated printing paper include
AURORA L (product of Nippon Paper industries Co., Ltd.) and KINMARI
Hi-L (product of Hokuetsu Paper Co., Ltd.). In addition, examples
of the cast-coated paper include MIRROR COAT G (product of Oji
Paper Co., Ltd.), SA KINFUJI PLUS (product of Oji Paper Co., Ltd.)
and HI-MCKINLEY ART (Product of Gojo Paper Mfg. Co., Ltd.).
[0036] Reaction Liquid
[0037] In the present invention, the reaction liquid is applied on
to the recording medium to aggregate and solidify a component
contained in the pigment ink, whereby a good image can be formed
with image defects such as bleeding and beading inhibited. In
addition, the resin-containing liquid applied to the image formed
with the pigment ink and the reaction liquid can also aggregate and
solidify a resin component by a reaction with the reaction liquid
to form a good resin layer.
[0038] Components of the reaction liquid and a method for applying
the reaction liquid on to the recording medium will hereinafter be
described.
[0039] Components of Reaction Liquid
[0040] The reaction liquid contains a viscosity increasing
component for the pigment ink. Here, the viscosity increase of the
pigment ink means not only a case where viscosity increase of the
whole pigment ink is recognized by contact of the pigment ink with
the viscosity increasing component, but also a case where topical
viscosity increase is caused by aggregation of a part of the
pigment ink.
[0041] For example, a metal ion or a polymer flocculant is used
without particular limitation as the viscosity increasing
component. However, a substance causing pH change of the pigment
ink to aggregate it is favorable, and an organic acid is more
favorable.
[0042] Examples of the organic acid include oxalic acid,
polyacrylic acid, formic acid, acetic acid, propionic acid,
glycolic acid, malonic acid, malic acid, maleic acid, ascorbic
acid, levulinic acid, succinic acid, glutaric acid, glutamic acid,
fumaric acid, citric acid, tartaric acid, lactic acid,
pyridonecarboxylic acid, pyronecarboxylic acid, pyrrolcarboxylic
acid, furancarboxylic acid, pyridinecarboxylic acid, coumalic acid,
thiophenecarboxylic acid, nicotinic acid, hydroxysuccinic acid and
dihydroxysuccinic acid. These acids may be used either singly or in
any combination thereof.
[0043] An aqueous medium may be used in the reaction liquid for
adjusting the viscosity and flowability thereof. Water or a mixed
solvent of water and a water-soluble organic solvent may be used as
the aqueous medium. The content of the water-soluble organic
solvent is favorably 3.0% by mass or more and 50.0% by mass or less
based on the total mass of the aqueous medium. No particular
limitation is imposed on the water-soluble organic solvent, and for
example, publicly known solvents are mentioned. Examples of the
water-soluble organic solvent include alcohols, glycols, alkylene
glycols the alkylene group of which has 2 to 6 carbon atoms,
polyethylene glycols, nitrogen-containing compounds and
sulfur-containing compounds. The water-soluble organic solvents may
be used either singly or in any combination thereof. Deionized
water (ion-exchanged water) is favorable as water. The content of
water is favorably 5.0% by mass or more and 95.0% by mass or less
based on the total mass of the aqueous medium. The content of the
aqueous medium is favorably 5% by mass or more and 60% by mass or
less based on the total mass of the reaction liquid though it
varies according to the kind of the viscosity increasing
component.
[0044] Various additives such as a resin particle, a water-soluble
resin, a surfactant, a pH adjustor, a rust preventive, a
preservative, a mildewproofing agent, an antioxidant, an
antireductant, an evaporation accelerator, a chelating agent and a
resin may be added into the reaction liquid as needed. However, any
additive inhibiting the storage stability of the reaction liquid
itself and aggregation is unfavorable. Incidentally, the surface
tension of the reaction liquid can be suitably adjusted by adding a
surfactant.
[0045] Reaction Liquid Applying Method
[0046] Any one of various methods heretofore known may be suitably
used. Examples thereof include die coating, blade coating, gravure
coating, offset coating and spray coating. The reaction liquid may
also be applied to the recording medium by using an ink jet method.
In addition, a combination of some methods thereof is also
extremely favorable.
[0047] Image Formation
[0048] The pigment ink and the resin-containing liquid are applied
to the recording medium to which the reaction liquid has been
applied. As a unit for applying these liquids to the recording
medium, an apparatus having a liquid ejection head of an ink jet
system is used. Examples of a liquid ejection system by an ink jet
method include a system in which film boiling of ink is caused by
an electrothermal converter to form a bubble, thereby ejecting the
ink, a system in which an ink is ejected by an electromechanical
convertor and a system in which an ink is ejected by using static
electricity. No particular limitation is imposed on the liquid
ejection system of the liquid ejection head, and any one of liquid
ejection heads of various systems may be used. Among others, the
liquid ejection head of the system using the electrothermal
converter is favorably used from the viewpoint of high-speed and
high-density printing in particular.
[0049] No particular limitation is imposed on the mode of the
liquid ejection head. A liquid ejection head of what is called a
shuttle mode in which printing is conducted while scanning the
liquid ejection head in a widthwise direction (for example, a
direction perpendicular to a conveying direction) of the recording
medium or a liquid ejection head of what is called a line head mode
in which ejection orifices are arranged in the form of a line in a
widthwise direction (for example, a direction perpendicular to a
conveying direction) of the recording medium may also be used.
[0050] Aqueous Pigment Ink
[0051] A pigment ink which can form an image with good
characteristics such as good weather resistance is used as an ink
for forming an image. The pigment ink is an aqueous pigment ink
containing a pigment as a coloring material and an aqueous liquid
medium. The aqueous pigment ink will hereinafter be also referred
to as a pigment ink merely. It is important for the pigment ink to
further contain an anionic polymer aggregatable by the reaction
liquid, and this anionic polymer mainly causes an aggregation
reaction with the reaction liquid, thereby increasing the viscosity
of the pigment ink to effectively inhibit the occurrence of
blurring or bleeding to form a good image.
[0052] No particular limitation is imposed on the anionic polymer
so long as it has an anionic functional group and is used in image
formation in combination with the reaction liquid. Among others, a
polymer composed of carboxylic acid, sulfonic acid or phosphonic
acid or having an anionic group obtained by neutralizing such an
acid with a metal salt or an organic amine is favorable. As
examples thereof, there may be mentioned acrylic polymers and
urethane polymers having a carboxyl group.
[0053] The anionic polymer is contained in the pigment ink as a
dispersant of a pigment as a coloring material and/or as various
additives.
[0054] The respective components of the pigment ink will
hereinafter be described.
[0055] Pigment
[0056] No particular limitation is imposed on a coloring material
of the pigment ink, i.e., a pigment that is a colorant component,
and a publicly known black pigment or a publicly known organic
pigment may be used. Specifically, a pigment represented by C.I.
(Color Index) Number may be used. In addition, carbon black is
favorably used as the black pigment. The content of the pigment in
the pigment ink is favorably 0.5% by mass or more and 15.0% by mass
or less, more favorably 1.0% by mass or more and 10.0% by mass or
less based on the total mass of the pigment ink.
[0057] Anionic Polymer
[0058] The anionic polymer may be contained in the pigment ink as a
soluble component and/or a dispersible component (for example, a
resin particle). The pigment ink favorably contains at least an
anionic polymer as a soluble component in that a better bright
image is formed.
[0059] Dispersant
[0060] As a dispersant in the case where a dispersant-dispersion
type pigment is used as a coloring material of an ink, any
dispersant may be used so long as it is used in an ink jet aqueous
ink. A water-soluble dispersant having both hydrophilic portion and
hydrophobic portion at the same time in its structure is favorably
used as the dispersant. In particular, a water-soluble resin
dispersant composed of a resin containing at least a hydrophilic
monomer and a hydrophobic monomer and obtained by copolymerizing
such monomers is favorably used. When an anionic polymer is
contained as the dispersant in the pigment ink, an anionic monomer
is used as the above hydrophilic monomer.
[0061] No particular limitation is imposed on the respective
monomers used here, and any monomers may be used so long as they
give a water-soluble resin having a function as the intended
dispersant. Specific examples of the hydrophobic monomer include
styrene, styrene derivatives, alkyl (meth)acrylates and benzyl
(meth)acrylate. Examples of the hydrophilic monomer include acrylic
acid, methacrylic acid and maleic acid.
[0062] The acid value of the water-soluble resin dispersant is
favorably 50 mg KOH/g or more and 550 mg KOH/g or less. The
weight-average molecular weight of the water-soluble resin
dispersant is favorably 1,000 or more and 50,000 or less, more
favorably 5,000 or more and 10,000 or less. The acid value and the
weight-average molecular weight in case where the anionic polymer
on which the reaction liquid acts is used as the water-soluble
resin dispersant are also favorably selected from these respective
ranges. Incidentally, the mass ratio of the pigment to the
dispersant is favorably within a range of from 1.0:0.1 to 1:3.
[0063] In addition, what is called a self-dispersion type anionic
pigment obtained by subjecting the pigment itself to surface
modification to enable dispersion in the aqueous liquid medium
component of the pigment ink may also be used as the pigment. When
the self-dispersion type anionic pigment is used without using the
dispersant, an anionic polymer is added into the pigment ink as
another additive than the dispersant. As examples of such an
additive, there may be mentioned the above-described anionic
polymer which can also be used as the dispersant and a resin
particle having an anionic group which will be described
subsequently.
[0064] Resin Particle
[0065] A colorless resin particle having no coloring material, for
example, a resin fine particle may be contained and used in the
pigment ink as an additive. Among others, the resin fine particle
is favorable because it may have an effect to improve image quality
and fixability in some case.
[0066] No particular limitation is imposed on the resin particle,
and one or more resin particles of a material and a particle size
that can be utilized in the intended image formation may be
suitably chosen for use. Specific examples of the material of the
resin particle include homopolymers such as polyolefin,
polystyrene, polyurethane, polyester, polyether, polyuria,
polyamide, polyvinyl alcohol, poly(meth)acrylic acid and salts
thereof, polyalkyl (meth)acrylates, and polydiene, and copolymers
obtained by combining a plurality of monomers among materials
forming these homopolymers.
[0067] The amount of the resin particle in the pigment ink is
favorably 1% by mass or more and 50% by mass or less, more
favorably 2% by mass or more and 40% by mass or less based on the
total mass of the pigment ink in that the aggregation reaction by
the viscosity increasing component in the reaction liquid is made
more effective, and liquid ejection performance by the liquid
ejection head is made good.
[0068] The resin particle is favorably contained in a state of
being dispersed in the aqueous liquid medium of the pigment ink. No
particular limitation is imposed on the mode of dispersion of the
resin particle in the pigment ink. However, a self-dispersion type
or dispersant-dispersion type resin particle is favorably used. The
self-dispersion type resin particle can be obtained by
homopolymerizing a monomer having a dissociable group or
copolymerizing plural kinds of such monomers. Examples of the
dissociable group include a carboxyl group, a sulfonic acid group
and a phosphoric acid group. Examples of the monomer having this
dissociable group include acrylic acid and methacrylic acid. A
polymer having an anionic group can be thereby obtained. When the
anionic polymer is contained in the pigment ink in the form of the
self-dispersion type resin particle, a self-dispersion type resin
particle having an anionic group is used as such a resin
particle.
[0069] The dispersant-dispersion type resin particle can be
dispersed in the ink by its combined use with a dispersant. The
dispersant may also be used in combination even when the
self-dispersion type resin particle is used. Any dispersant may be
used without particular limitation as the dispersant for dispersing
the resin particle, for example, an emulsifier, so long as it can
achieve the intended resin fine particle-dispersing effect
irrespective of those of a low molecular weight or a high molecular
weight. A surfactant may be used as such an emulsifier, and a
nonionic surfactant or a surfactant having the same electric charge
as the resin particle is favorable. When the resin particle having
the anionic group is used, an anionic surfactant is favorably
used.
[0070] The resin particle is desirably a fine particle having a
dispersion particle size of 10 nm or more and 1,000 nm or less,
more desirably a fine particle having a dispersion particle size of
100 nm or more and 500 nm or less.
[0071] Upon preparation of the pigment ink, the resin particle is
favorably used in the form of a resin particle dispersion dispersed
in a liquid (for example, an aqueous medium such as water). It is
also favorable to add various kinds of additives upon preparation
of the resin particle dispersion from the viewpoint of
stabilization. As the additive for this stabilization, for example,
n-hexadecane, dodecyl methacrylate, stearyl methacrylate,
chlorobenzene, dodecylmercaptan, olive oil, a blue dye (Blue 70) or
polymethyl methacrylate is favorable.
[0072] Surfactant
[0073] The pigment ink may contain a surfactant. Specific examples
of the surfactant include ACETYLENOL EH (product of Kawaken Fine
Chemicals Co., Ltd.) and ADEKA PLURONIC (product of Adeka
Corporation). The amount of the surfactant in the pigment ink is
favorably 0.01% by mass or more and 5.0% by mass or less based on
the total mass of the pigment ink.
[0074] The surface tension of the pigment ink is favorably
controlled to 25 mN/m or more and 45 mN/m or less in consideration
of ink jet ejection suitability, and the relationship of the
surface tension with the resin-containing liquid is set within a
range corresponding to the present invention. That is, the surface
tension of the pigment ink in the present invention is adjusted to
be lower than the surface tension of a resin-containing liquid
which will be described subsequently. This adjustment of the
surface tension can be made by controlling the amount of the
surfactant added.
[0075] Water and Water-Soluble Organic Solvent
[0076] The pigment ink is prepared by using at least a pigment as a
coloring material and an aqueous liquid medium as a dispersion
medium of the pigment. Water or a mixture of water and a
water-soluble organic solvent may be used as the aqueous liquid
medium. Water is favorably water deionized by ion exchange. The
content of water in the pigment ink is favorably 30% by mass or
more and 97% by mass or less based on the total mass of the pigment
ink.
[0077] No particular limitation is imposed on the kind of the
water-soluble organic solvent, and any solvent may be used so long
as it can be utilized in an ink jet ink. Specific examples thereof
include glycerol, diethylene glycol, polyethylene glycol and
2-pyrrolidone. At least one of the water-soluble organic solvents
may be used. The content of the water-soluble organic solvent in
the pigment ink is favorably 3% by mass or more and 70% by mass or
less based on the total mass of the pigment ink.
[0078] Other Additives
[0079] The pigment ink may also contain various additives such as a
pH adjustor, a rust preventive, a preservative, a mildewproofing
agent, an antioxidant, an antireductant, a surface modifier, a
water-soluble resin and a neutralizer thereof, and a viscosity
modifier other than the above-described components as needed.
[0080] Resin-Containing Aqueous Liquid
[0081] In order to improve gloss-related characteristics such as
glossiness and gloss uniformity of an image to form an image having
high glossiness and gloss uniformity, i.e., a bright image, an
image formed on a recording medium with the reaction liquid and the
pigment ink is treated with a resin-containing aqueous liquid. The
resin-containing aqueous liquid will hereinafter be also referred
to as the resin-containing liquid merely. This resin-containing
liquid contains at least an anionic polymer as a component capable
of causing the aggregation reaction by the reaction liquid.
[0082] The resin-containing liquid may be any liquid so long as the
treatment with such a liquid does not affect the image formed with
the pigment ink, and it can form the intended bright image having
high glossiness and gloss uniformity, and is favorably transparent,
colorless transparent, milky white or white. Therefore, the ratio
of a maximum absorbance to a minimum absorbance (maximum
absorbance/minimum absorbance) of a liquid composition in a
wavelength range of from 400 nm to 800 nm which is a wavelength
range of visible light is favorably 1.0 or more and 2.0 or less.
This means that the liquid composition does not substantially have
an absorbance peak in the wavelength range of the visible light, or
the intensity of the peak is extremely small if any. In addition,
the resin-containing liquid favorably contains no coloring
material. The absorbance can be measured by means of Hitachi Double
Beam Spectrophotometer U-2900 (manufactured by Hitachi
High-Technologies Corporation) by using a non-diluted
resin-containing liquid. Incidentally, the resin-containing liquid
may also be diluted to measure the absorbance. The reason for this
is that a value of the ratio of the maximum absorbance to the
minimum absorbance (maximum absorbance/minimum absorbance) does not
depend on a dilution rate because both maximum absorbance and
minimum absorbance are proportional to the dilution rate.
[0083] The anionic polymer may be contained in the resin-containing
liquid as a soluble component and/or a dispersible component (for
example, a resin particle). The resin-containing liquid favorably
contains at least the anionic polymer as the soluble component in
that a better bright image is formed. The content of the anionic
polymer is favorably 1% by mass or more and 15% by mass or less,
more favorably 3% by mass or more and 10% by mass or less based on
the total mass of the resin-containing liquid in consideration of a
gloss-developing effect and ink jet ejection suitability.
[0084] In the present invention, the resin-containing liquid is
aqueous, and the surface tension of this aqueous resin-containing
liquid, i.e., a resin-containing aqueous liquid, is required to be
higher than the surface tension of the aqueous pigment ink for
preventing the occurrence of image cracking. By doing so,
permeation of the resin-containing liquid into the interior of a
coloring layer by the pigment ink on the recording medium can be
delayed or prevented to develop an effect of inhibiting the
occurrence of image cracking caused by cracks that generate from
the interior of the coloring layer by the pigment ink.
[0085] The respective components of the resin-containing liquid
will hereinafter be described.
[0086] Water-Soluble Resin
[0087] When the resin-containing liquid contains an anionic polymer
as a soluble component of an aqueous liquid medium, a water-soluble
anionic polymer having both hydrophilic portion and hydrophobic
portion at the same time in its structure is favorably used as the
anionic polymer from the viewpoint of good solubility in the
resin-containing liquid. In particular, a resin containing at least
a hydrophilic monomer and a hydrophobic monomer and obtained by
copolymerizing such monomers is favorably used. An anionic group is
used as the hydrophilic group for achieving the effect of the
present invention. Specific examples of the anionic group include
acrylic acid, methacrylic acid and maleic acid. Examples of the
hydrophobic monomer include styrene, styrene derivatives, alkyl
(meth)acrylates and benzyl (meth)acrylate.
[0088] When the water-soluble anionic polymer is used, the acid
value thereof is favorably 50 mg KOH/g or more and 550 mg KOH/g or
less. The acid value is favorably lower for accelerating
aggregation and solidification from the viewpoint of formation of a
good image.
[0089] The weight-average molecular weight of the water-soluble
anionic polymer is favorably 1,000 or more and 50,000 or less, more
favorably 5,000 or more and 10,000 or less.
[0090] Resin Particle
[0091] A colorless resin particle having no coloring material, for
example, a resin fine particle may be contained and used in the
resin-containing liquid as an additive. Among others, the resin
fine particle is favorable because it may have an effect to improve
image quality and fixability in some case.
[0092] No particular limitation is imposed on the resin particle,
and one or more resin particles of a material and a particle size
that can be utilized in the intended image formation may be
suitably chosen for use. Specific examples of the material of the
resin particle include homopolymers such as polyolefin,
polystyrene, polyurethane, polyester, polyether, polyurea,
polyamide, polyvinyl alcohol, poly(meth)acrylic acid and salts
thereof, polyalkyl (meth)acrylates, and polydiene, and copolymers
obtained by combining a plurality of monomers among materials
forming these homopolymers.
[0093] The amount of the resin particle in the resin-containing
liquid is favorably 1% by mass or more and 50% by mass or less,
more favorably 2% by mass or more and 40% by mass or less based on
the total mass of the resin-containing liquid in that the
aggregation reaction by the viscosity increasing component in the
reaction liquid is made more effective, and liquid ejection
performance by the liquid ejection head is made good.
[0094] The resin particle is favorably contained in a state of
being dispersed in a liquid medium of the resin-containing liquid.
No particular limitation is imposed on a mode of the dispersion of
the resin particle in the resin-containing liquid. However, a
self-dispersion type or dispersant-dispersion type resin particle
is favorably used. The self-dispersion type resin particle can be
obtained by homopolymerizing a monomer having a dissociable group
or copolymerizing plural kinds of such monomers. Examples of the
dissociable group include a carboxyl group, a sulfonic acid group
and a phosphoric acid group. Examples of the monomer having this
dissociable group include acrylic acid and methacrylic acid. A
polymer having an anionic group can be thereby obtained. When the
anionic polymer is contained in the resin-containing liquid in the
form of the self-dispersion type resin particle, a self-dispersion
type resin particle having an anionic group is used as such a resin
particle.
[0095] The dispersant-dispersion type resin particle can be
dispersed in the resin-containing liquid by its combined use with a
dispersant. The dispersant may also be used in combination even
when the self-dispersion type resin particle is used. Any
dispersant may be used without particular limitation as the
dispersant for dispersing the resin particle, for example, an
emulsifier, so long as it can achieve the intended resin fine
particle-dispersing effect irrespective of those of a low molecular
weight or a high molecular weight. A surfactant may be used as such
an emulsifier, and a nonionic surfactant or a surfactant having the
same electric charge as the resin particle is favorable. When a
resin particle having an anionic group is used, an anionic
surfactant is favorably used. If the anionic polymer as an
essential component for the above-described resin-containing liquid
has a function as a dispersant of the resin particle, this anionic
polymer can be used as a dispersant of the resin particle.
[0096] The resin particle is desirably a fine particle having a
dispersion particle size of 10 nm or more and 1,000 nm or less,
more desirably a fine particle having a dispersion particle size of
100 nm or more and 500 nm or less.
[0097] Upon preparation of the resin-containing liquid, the resin
particle is favorably used in the form of a resin particle
dispersion dispersed in a liquid (for example, an aqueous medium
such as water). It is also favorable to add various kinds of
additives upon preparation of the resin particle dispersion from
the viewpoint of stabilization. As the additive for this
stabilization, for example, n-hexadecane, dodecyl methacrylate,
stearyl methacrylate, chlorobenzene, dodecylmercaptan, olive oil, a
blue dye (Blue 70) or polymethyl methacrylate is favorable.
[0098] Surfactant
[0099] The resin-containing liquid may contain a surfactant.
Specific examples of the surfactant include ACETYLENOL EH (product
of Kawaken Fine Chemicals Co, Ltd.) and ADEKA PLURONIC (product of
Adeka Corporation). The amount of the surfactant in the
resin-containing liquid is favorably 0.01% by mass or more and 5.0%
by mass or less based on the total mass of the resin-containing
liquid.
[0100] In order to achieve the effect of the present invention,
however, the surface tension of the resin-containing liquid is
required to be controlled to be higher than the surface tension of
the pigment ink. In addition, the surface tension of the
resin-containing liquid is favorably 3 mN/m or more higher, more
favorably 5 mN/m or more higher than the surface tension of the
pigment ink. The amount of the surfactant added is adjusted so as
to achieve the above requirement. Incidentally, the upper limit of
a difference between these surface tensions may be set to be about
10 mN/m.
[0101] Water and Water-Soluble Organic Solvent
[0102] The resin-containing liquid is prepared by using at least an
anionic polymer and an aqueous liquid medium. Water or a mixture of
water and a water-soluble organic solvent may be used as the
aqueous liquid medium. Water is favorably water deionized by ion
exchange. The content of water in the resin-containing liquid is
favorably 30% by mass or more and 97% by mass or less based on the
total mass of the resin-containing liquid.
[0103] No particular limitation is imposed on the kind of the
water-soluble organic solvent, and any solvent may be used so long
as it can be used in the preparation of the intended
resin-containing liquid. Specific examples thereof include
glycerol, diethylene glycol, polyethylene glycol and 2-pyrrolidone.
At least one of the water-soluble organic solvents may be used. The
content of the water-soluble organic solvent in the
resin-containing liquid is favorably 3% by mass or more and 70% by
mass or less based on the total mass of the resin-containing
liquid.
[0104] Other Additives
[0105] The resin-containing liquid may also contain various
additives such as a pH adjustor, a rust preventive, a preservative,
a mildewproofing agent, an antioxidant, an antireductant, a surface
modifier, a water-soluble resin and a neutralizer thereof, and a
viscosity modifier other than the above-described components as
needed.
[0106] By applying the resin-containing liquid on to the coloring
layer formed by the pigment ink on the recording medium,
aggregation and solidification are caused by a reaction with the
viscosity increasing component of the reaction liquid applied to
the recording medium in advance, thereby forming a film by at least
a resin of the resin-containing liquid applied to the surface of
the coloring layer.
[0107] Drying after Application of Resin-Containing Liquid
[0108] The permeation of the resin-containing liquid into the
interior of the coloring layer by the pigment ink is delayed by
making the surface tension of the resin-containing liquid higher
than the surface tension of the pigment ink, and in the delayed
state film formation on the surface of the coloring layer is
conducted by the viscosity increase of the resin-containing liquid,
for example, aggregation and solidification as well as evaporation
of a remaining solvent component.
[0109] In addition, a drying step of removing water from the image
formed on the recording medium after the application of the
resin-containing liquid is favorably provided. The evaporation of
the remaining water in the image formed on the recording medium is
accelerated, whereby the resin film formation by the application of
the resin-containing liquid is advanced to more reduce the amount
of permeation of the resin-containing liquid into the coloring
layer, so that the image-cracking-preventing effect becomes more
remarkable. From the above, it is favorable to provide the drying
step after the application of the resin-containing liquid.
[0110] For the same reason as in the direct drawing type ink jet
recording method, it is favorable to provide a step of removing
water from an intermediate image formed on a transfer member (first
recording medium) in a transfer type ink jet recording method which
will be described subsequently.
[0111] Any of a heating method, a method of supplying low-humidity
air, a pressure-reducing method and a method of combining these
methods is suitably used as a drying method.
[0112] Estimated Mechanism of Occurrence of Image Cracking
[0113] By further treating the image formed on the recording medium
with the resin-containing liquid, fixing of the image is
accelerated, and further improvement in glossiness and gloss
uniformity is achieved, whereby a bright image having high
glossiness and gloss uniformity can be formed.
[0114] An estimated mechanism of image cracking generated upon the
formation of the bright image will now be described with reference
to FIGS. 2A to 2C.
[0115] FIGS. 2A to 2C are drawings schematically illustrating a
state of image formation in the sectional views in a thickness-wise
direction of a recording medium. Droplets of a pigment ink are
applied to a reaction liquid layer 22 applied on to a recording
medium 21. The droplets of the pigment ink react with a viscosity
increasing component contained in the reaction liquid layer 22 to
form a coloring layer 23 forming an image in its
viscosity-increased state. In the surface of the coloring layer 23,
there are linking sites or stacking sites of dots; thus, it is
considered that the interspace through which a liquid permeates
into the interior of the coloring layer is ununiformly present in
the whole layer. A resin-containing liquid 24 applied to the
surface of the coloring layer 23 permeates into the interspace in
the coloring layer 23 in the direction illustrated in FIG. 2A to
cause an aggregation and solidification reaction with the reaction
liquid present on the surface of the recording medium or in the
interior of the coloring layer 23. Since the aggregation and
solidification reaction of the resin-containing liquid having
permeated into the ununiformly present interspace affects the
coloring layer itself, that is, uneven aggregation and shrinkage
stress is caused in directions of the arrows illustrated in FIG. 2B
in the interior of the coloring layer 23, it is thus inferred that
cracks are generated in the interior of the coloring layer 23 as
illustrated in FIG. 2C to cause image cracking.
[0116] For example, when solidification is sufficiently accelerated
by acceleration of aggregation of the coloring layer 23 or by
drying and evaporation of a solvent component in the
resin-containing liquid if the uneven aggregation and shrinkage
stress of the resin-containing liquid is caused, it is known that
the occurrence of the image cracking can be inhibited.
[0117] However, the interval between ejection of the pigment ink
and ejection of the resin-containing liquid is very short and is
about 100 ms, so that the coloring layer formed by the pigment ink
cannot form a hard state sufficient to prevent the occurrence of
the image cracking due to the influence of remaining water. In
other words, the pigment ink droplet after the contact with the
reaction liquid retains a liquid state having a surface tension.
Accordingly, the image is moved by the uneven aggregation and
shrinkage stress of the resin-containing liquid, so that it may be
difficult in some cases to avoid the occurrence of the image
cracking.
[0118] In the present invention, the permeation of the
resin-containing liquid into the interior of the coloring layer
formed by the pigment ink is delayed by making the surface tension
of the resin-containing liquid higher than the surface tension of
the pigment ink, whereby the image cracking of the coloring pigment
ink layer caused by the occurrence of the uneven aggregation and
shrinkage stress can be prevented even under an environment of
high-speed printing. A liquid with low surface tension generally
has a nature of wetting and spreading into a liquid with high
surface tension. Since the surface tension of the resin-containing
liquid is higher than the pigment ink in the present invention, the
flowing of a liquid is directed toward the resin-containing liquid
from the pigment ink. It is thus considered that the permeation
itself of the resin-containing liquid into the coloring layer
formed by the pigment ink is delayed. When the difference between
the surface tensions is 3 mN/m or more, the
image-cracking-preventing effect by the delay of the permeation
becomes remarkable. It is considered that in the delayed state of
the permeation, evaporation of water in the resin-containing liquid
as well as aggregation and solidification occur on the surface of
the coloring layer formed by the pigment ink, and consequently such
a state that a film of the resin-containing liquid is formed on the
surface of the coloring layer can be created with the image
cracking prevented. Incidentally, regarding the coloring layer
formed by the contact between the pigment ink droplet and the
reaction liquid, the surface tension of an upper portion of the
coloring layer upon the contact with the resin-containing liquid is
dominated by the surface tension of the pigment ink forming the
coloring layer. It is thus considered that regarding the reaction
liquid located under the coloring layer, the influence of the
surfactant in the reaction liquid is hard to be reflected in the
upper portion of the coloring layer on which the resin-containing
liquid impacts. In other words, it is inferred that the reaction
liquid and the ink do not sufficiently mix at the interval between
ejection of the pigment ink and ejection of the resin-containing
liquid.
[0119] (2) Transfer Type Ink Jet Recording Method
[0120] FIG. 4 schematically illustrates a transfer type ink jet
recording apparatus. In FIG. 4, a transfer member 40 which is a
first recording medium includes a support member 42 of a rotatable
drum form and a surface layer member 41 arranged on an outer
peripheral surface of the support member 42. The transfer member 40
(support member 42) is rotationally driven in a direction
(anticlockwise direction) of the arrow on a rotational shaft 43.
The apparatus is so constructed that respective structures
(members) arranged around the transfer member 40 are operated in
synchronization with the rotation of the transfer member 40. A
reaction liquid is applied to the transfer member 40 by a roller
type coating device 44. This roller type coating device 44 has a
coating roller system composed of a reaction liquid tank for
storing a reaction liquid 52, a coating roller for applying the
reaction liquid to the surface of the surface layer member and a
supply roller for supplying the reaction liquid to the coating
roller from the reaction liquid tank. A pigment ink is applied from
a liquid ejection head (recording head) 45 of an ink jet system to
form an intermediate image, which is a mirror-inverted image of a
desired image, on the transfer member 40. At that time, a component
contained in the pigment ink is aggregated by contact of the
reaction liquid applied on to the transfer member 40 in advance
with the coloring pigment ink to form a coloring ink layer.
[0121] When the transfer member 40 reaches a position of a liquid
ejection head 51, a resin-containing liquid is applied on to the
image formed in advance. The resin-containing liquid is also
aggregated by contact with the reaction liquid like the pigment ink
to form a resin layer containing no coloring material on the image.
Thereafter, the temperature of the intermediate image formed on the
transfer member may also be controlled by a temperature controlling
mechanism 47 so as to become a desired temperature. At this time, a
liquid in the intermediate image formed on the transfer member may
also be removed by a liquid removing mechanism 46. A second
recording medium 48 is then bright into contact with the transfer
member 40 by means of a pressure roller 49 to transfer the
intermediate image to the second recording medium 48. A cleaning
unit 50 may also be provided as a unit for cleaning the surface of
the transfer member after the intermediate image is transferred to
the second recording medium 48. Incidentally, the same one as the
recording medium used in the above-described direct drawing type
ink jet recording method may be used as the second recording medium
48. In addition, as for the reaction liquid, the aqueous pigment
ink and the resin-containing aqueous liquid, the same ones as the
reaction liquid, the aqueous pigment ink and the resin-containing
aqueous liquid which are used in the above-described direct drawing
type ink jet recording method may be used.
[0122] Transfer Member
[0123] The transfer member which is the first recording medium is a
recording medium for holding a liquid composition and an ink, on
which an intermediate image is recorded. An example of the transfer
member includes one having a support member for handling the
transfer member itself and transmitting necessary force and a
surface layer member on which the intermediate image is recorded.
Incidentally, the support member and the surface layer member may
be formed integrally.
[0124] As examples of the shape of the transfer member, there may
be mentioned a sheet-shape, a roller-shape, a drum-shape, a
belt-shape and an endless web-shape. The size of the transfer
member may be suitably set according to the size of a recordable
transfer medium.
[0125] The support member of the transfer member is required to
have certain strength from the viewpoints of conveyance accuracy
and durability thereof. A metal, ceramic or resin is favorable as a
material of the support member. Among these, aluminum, iron,
stainless steel, acetal resin, epoxy resin, polyimide,
polyethylene, poly(ethylene terephthalate), nylon, polyurethane,
silica ceramic or alumina ceramic is favorable. When the support
member is formed by such a material, stiffness capable of
withstanding a pressure upon transfer and dimensional accuracy can
be secured, and moreover inertia upon operation can be relieved to
improve the responsiveness of control. Incidentally, these
materials may be used either singly or in any combination
thereof.
[0126] The surface layer of the transfer member is required to have
certain elasticity for transferring the intermediate image to the
transfer medium such as paper. Supposing that, for example, paper
is used as the transfer medium, the surface layer of the transfer
member favorably has a Durometer Type A hardness (according to JIS
K 6253) of 10.degree. or more and 100.degree. or less, more
favorably 20.degree. or more and 60.degree. or less. A metal,
ceramic or resin is favorable as a material of the surface layer
member forming a surface layer of the transfer member. Among these,
polybutadiene rubber, nitrile rubber, chloroprene rubber, silicone
rubber, fluorine-containing rubber, fluorosilicone rubber, urethane
rubber, styrene rubber, olefin elastomer, vinyl chloride elastomer,
ester elastomer, amide elastomer, polyether, polyester,
polystyrene, polycarbonate, siloxane compounds or perfluorocarbon
compounds are favorable, and the siloxane compound is more
favorable. The surface layer member may also be formed by
laminating a plurality of materials. Examples thereof include a
material obtained by laminating silicone rubber on an endless
belt-shaped urethane rubber sheet and a material obtained by
forming a film of a siloxane compound on a urethane rubber
sheet.
[0127] In addition, the surface of the transfer member may be
subjected to a surface treatment before use. Examples of the
surface treatment include a flame treatment, a corona treatment, a
plasma treatment, a polishing treatment, a roughening treatment, an
active energy ray irradiation treatment, an ozone treatment, a
surfactant treatment and a silane coupling treatment. Some of these
treatment may also be used in combination.
[0128] In addition, the surface arithmetic mean roughness of the
surface of the transfer member is favorably 0.01 .mu.m or more and
3 .mu.m or less as prescribed in JIS B 0601:2001 from the viewpoint
of inhibiting the flowing of the intermediate image on the transfer
member. Further, the contact angle to water of the surface of the
transfer member is favorably 50.degree. or more and 110.degree. or
less, more favorably 60.degree. or more and 100.degree. or
less.
EXAMPLES
[0129] The present invention will hereinafter be described more
specifically by Examples of the image forming method according to
the present invention. The present invention is not limited by the
following Examples unless going beyond the gist thereof.
Incidentally, all designations of "part" or "parts" and "%" are
based on mass unless expressly noted.
[0130] Image Formation According to Direct Drawing Type Ink Jet
Recording Method
[0131] An image was formed by using a direct drawing type ink jet
image forming apparatus illustrated in FIG. 1. Coat paper (MIRROR
COAT G, ream weight: 127.9 g/m.sup.2, product of Oji Paper Co.,
Ltd.) was used as a recording medium. The sheet fixing member for
fixing the coat paper was temperature-controllable to set its
temperature to 50.degree. C. In addition, the coating weight of a
reaction liquid applied on to the coat paper was set to 1
g/m.sup.2. Further, both liquid ejection device for a pigment ink
and liquid ejection device for a resin-containing liquid have a
liquid ejection head of a type in which an ink is ejected by an
On-Demand system using an electrothermal converter. These liquid
ejection heads take a line head mode in which ejection orifices are
arranged linearly in a direction perpendicular to a conveying
direction of the coat paper.
[0132] An image was formed by setting each of ejection amounts of
the pigment ink and the resin-containing liquid and nozzle
resolution to 3.0 pl and 1,200 dpi, respectively.
[0133] In this example, the case where four ejections are performed
on a region 600 dpi long and 600 dpi wide was defined as 100% duty.
After the reaction liquid was applied to the coat paper, a solid
image of 200% duty or 300% duty was formed with the pigment ink,
and the resin-containing liquid was then ejected at 200% duty on
the image, thereby forming a bright image having high glossiness
and gloss uniformity. In addition, the interval between the
ejection of the pigment ink and the ejection of the
resin-containing liquid was set to 100 ms. In the case where a hot
air drying device was used, hot air drying was conducted for 5
seconds under conditions of a temperature proximately above the
paper surface of 90.degree. C. and a wind velocity of 7 m/s after
several tens milliseconds from the formation of the bright
image.
[0134] Reaction Liquid
[0135] The reaction liquid used in the present invention was
prepared by mixing components of the following composition,
sufficiently stirring the resultant mixture and then filtering the
mixture under pressure through a microfilter (product of Fuji Photo
Film Co., Ltd.) having a pore size of 3.0 .mu.m.
Citric acid: 30.0%
Glycerol: 15.0%
[0136] ACETYLENOL EH (product of Kawaken Fine Chemicals Co., Ltd.):
1.0% Pure water: 54.0%
[0137] Pigment Ink
[0138] A black pigment ink was used in this example. The
preparation procedure thereof will hereinafter be described.
[0139] 1) Preparation of Black Pigment Dispersion Liquid
[0140] Ten percent of carbon black (trade name: Monarch 1100,
product of Cabot Co.), 15% of an aqueous solution of a pigment
dispersant (styrene-ethyl acrylate-acrylic acid terpolymer, acid
value: 150 mg KOH/g, weight-average molecular weight: 8,000, solid
content: 20%, neutralized with potassium hydroxide) and 75% of pure
water were mixed. A batch type vertical sand mill (manufactured by
IMEX Co.) was charged with the resultant mixture and 200% of
zirconia beads having a diameter of 0.3 mm to conduct a dispersing
treatment for 5 hours while cooling with water. The thus-obtained
dispersion liquid was centrifuged by a centrifugal separator to
remove coarse particles, thereby obtaining a black pigment
dispersion liquid having a pigment concentration of about 10%. This
black pigment dispersion liquid was used in preparation of a
pigment ink which will be described subsequently.
[0141] 2) Preparation of Resin Fine Particle Dispersion
[0142] Eighteen percent of butyl methacrylate, 2% of
2,2'-azobis-(2-methylbutyronitrile) and 2% of n-hexadecane were
mixed and stirred for 0.5 hours. This mixture was added dropwise to
78% of a 6% aqueous solution of NIKKOL BC15 (product of Nikko
Chemicals Co., Ltd.), which is an emulsifier, and the resultant
mixture was stirred for 0.5 hours. The mixture was then irradiated
with ultrasonic waves for 3 hours by an ultrasonic wave irradiation
machine. A polymerization reaction was then conducted for 4 hours
at 80.degree. C. under a nitrogen atmosphere, and filtration was
conducted after cooling at room temperature to obtain a resin fine
particle dispersion having a concentration of about 20%. The
mass-average molecular weight of the resin fine particle was about
1,000 or more and about 2,000,000 or less, and the dispersion
particle size thereof was about 100 nm or more and about 500 nm or
less. This resin fine particle dispersion was used in preparation
of the pigment ink and Resin-containing liquids 8, 9 which will be
described subsequently.
[0143] 3) Preparation of Pigment Ink
[0144] A black ink having the following composition was prepared.
Specifically, the black ink was obtained by mixing components of
the following formulation, sufficiently stirring the resultant
mixture and then filtering the mixture under pressure through a
microfilter (product of Fuji Photo Film Co., Ltd.) having a pore
size of 3.0 .mu.m.
[0145] Formulation
Black pigment dispersion liquid (concentration: about 10%): 20%
Resin fine particle dispersion (concentration: about 20%): 50%
Glycerol: 5%
[0146] Diethylene glycol: 7% L31 (product of Adeka Corporation):
1.5% Pure water: 17.5%
[0147] Preparation of Resin-Containing Liquid
[0148] The compositions of respective resin-containing liquids used
in this example are as shown in the following Table 1. After
respective components were mixed and sufficiently stirred, the
resultant mixtures were filtered under pressure through a
microfilter (product of Fuji Photo Film Co., Ltd.) having a pore
size of 3.0 .mu.m, thereby preparing the respective
resin-containing liquids.
TABLE-US-00001 TABLE 1 Resin- Resin containing particle Pure liquid
Resin component dispersion glycerol Surfactant water 1 Resin 1
10.0% -- 7.0% 1.0% 82.0% 2 Resin 1 10.0% -- 7.0% 0.6% 82.4% 3 Resin
1 10.0% -- 7.0% 0.4% 82.6% 4 Resin 1 10.0% -- 7.0% 0.2% 82.8% 5
Resin 1 10.0% -- 7.0% 0.1% 82.9% 6 Resin 2 8.0% -- 7.0% 1.0% 84.0%
7 Resin 2 8.0% -- 7.0% 0.1% 84.9% 8 Resin 1 3.0% 25.0% 7.0% 1.0%
64.0% 9 Resin 1 3.0% 25.0% 7.0% 0.1% 64.9% 10 Resin 1 3.0% 25.0%
7.0% 0.4% 64.6% 11 Resin 1 3.0% 25.0% 7.0% 0.2% 64.8% 12 Resin 1
3.0% 25.0% 7.0% 0.15% 64.85%
Resin particle dispersion: The resin particle dispersion prepared
in "2) Preparation of resin fine particle dispersion" Surfactant:
ACETYLENOL EH (product of Kawaken Fine Chemicals Co., Ltd.) Resin 1
(anionic polymer): A styrene-acryl-butyl acrylate terpolymer (acid
value: 120 mg KOH/g, molecular weight: 12,000) Resin 2 (anionic
polymer): A styrene-acryl-butyl acrylate terpolymer (acid value: 90
mg KOH/g, molecular weight: 12,000)
[0149] Comparison of surface tensions of pigment ink and respective
resin-containing liquids
[0150] The surface tensions of the pigment ink and the respective
resin-containing liquids prepared above are shown in the following
Table 2. Incidentally, each surface tension was measured by an
automatic surface tensiometer (manufactured by Kyowa Interface
Science Co., Ltd.).
TABLE-US-00002 TABLE 2 Surface tension (mN/m) Pigment ink 37.0
Resin-containing liquid 1 31.5 Resin-containing liquid 2 36.5
Resin-containing liquid 3 38.0 Resin-containing liquid 4 40.0
Resin-containing liquid 5 43.0 Resin-containing liquid 6 31.0
Resin-containing liquid 7 39.5 Resin-containing liquid 8 31.0
Resin-containing liquid 9 43.0 Resin-containing liquid 10 38.0
Resin-containing liquid 11 40.0 Resin-containing liquid 12 42.0
[0151] Examples and Comparative Examples of the present invention
will hereinafter be described.
Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-4
[0152] Each of the resin-containing liquids shown in Table 1 was
used as the resin-containing liquid to form a bright image by image
formation according to the above-described direct drawing type ink
jet recording method. A drying method after the formation of the
bright image is shown in Table 4. Incidentally, the natural drying
is a drying method in which the image is left to stand without
using a hot air drying device, and the hot air drying is a drying
method in which hot air is allowed to blow against the image by
using a hot air drying device.
[0153] Evaluation of Image-Cracking-Inhibiting Effect
[0154] Image formation was conducted according to the conditions of
respective Examples and Comparative Examples to quantitatively
compare the degrees of image cracking generated at that time. The
image formation was conducted by forming a 300% duty solid image
with the pigment ink and then ejecting each resin-containing liquid
at 200% duty on that solid image. Regarding the quantification of
the image cracking, the surface (500 .mu.m.times.700 .mu.m) of the
bright image taken in a dark field with an optical microscope was
taken into a commercially-available image processing software
(Adobe Photoshop CS5, product of Adobe Systems Inc.) to convert it
to a gray scale image, thereby obtaining a two-gradation image. An
image illustration when converted to the two-gradation image is
illustrated in FIG. 3, and in this illustration, the image is
divided into an image portion 31 and a crack portion 32.
Thereafter, the proportion of the number of pixels in a 255
gradation area (the number of pixels in the image cracking portion)
to the number of pixels in the whole image (proportion of the image
cracking portion) is quantitatively determined to evaluate the
degree of the image cracking according to the criterion shown in
following Table 3.
TABLE-US-00003 TABLE 3 Proportion of image cracking portion
Evaluation 0% or more and less than 2% A 2% or more and less than
3% B 3% or more and less than 5% C 5% or more and less than 15% D
15% or more E
[0155] Results obtained by comparing the degrees of the image
cracking by using the above-described quantitative method are shown
in Table 4.
TABLE-US-00004 TABLE 4 Degree of image Resin-containing liquid
Drying method cracking Ex. 1-1 3 Natural drying C Ex. 1-2 4 Natural
drying B Ex. 1-3 5 Natural drying A Ex. 1-4 7 Natural drying C Ex.
1-5 7 Hot air drying B Ex. 1-6 9 Natural drying A Ex. 1-7 10
Natural drying C Ex. 1-8 11 Natural drying B Ex. 1-9 12 Natural
drying A Comp. 1 Natural drying D Ex. 1-1 Comp. 2 Natural drying D
Ex. 1-2 Comp. 6 Natural drying E Ex. 1-3 Comp. 8 Natural drying D
Ex. 1-4
Example 1-10
Evaluation of Glossiness and Gloss Uniformity
[0156] An image obtained by conducting printing on coat paper
(MIRROR COAT G, product of Oji Paper Co., Ltd.) at 200% duty or
300% duty with the above-described pigment ink by means of the
direct drawing type ink jet image forming apparatus used in Example
1-1 and then ejecting Resin-containing liquid 4, and an image
obtained by conducting only the printing at 200% duty or 300% duty
with the pigment ink were subjected to glossiness measurement.
PG-II/IIM (manufactured by Nippon Denshoku Industries Co., Ltd.)
was used in the glossiness measurement to measure gloss at
20.degree.. In addition, the gloss value (expressed as a GB1 value)
at 20.degree. was measured at ten points on the image. Measured
results were evaluated according to the following criterion.
A: The measured value is distributed between 55 or more and 60 or
less in terms of the GB1 value B: The measured value is distributed
between 50 or more and less than 55 in terms of the GB1 value C:
The measured value is distributed between 45 or more and less than
50 in terms of the GB1 value
[0157] Results obtained by comparing the gloss values according to
the above criterion are shown in Table 5.
TABLE-US-00005 TABLE 5 Evaluation result according to Kind of image
according to recording conditions GB1 value Image obtained by
ejecting Resin-containing A liquid 4 at 200% duty on 200% duty
image by pigment ink Image obtained by ejecting Resin-containing A
liquid 4 at 200% duty on 300% duty image by pigment ink Image
obtained by conducting only the printing C at 200% duty by pigment
ink Image obtained by conducting only the printing B at 300% duty
by pigment ink
[0158] It is understood from Table 5 that the image obtained by
ejecting the resin-containing liquid had the high glossiness value,
and the glossiness thereof is uniform irrespective of images.
[0159] From the above, it is understood that when the surface
tension of the resin-containing liquid is higher than that of the
pigment ink, the image-cracking-inhibiting effect is achieved, and
a more remarkable effect is developed when the difference in
surface tension is 3 mN/m or more. In Comparative Example 1-3, the
proportion of the image cracking portion is as large as 15% or
more, because the resin with the low acid value is used as the
water-soluble resin in the resin-containing liquid, resulting in
such a condition that image cracking is easily generated. Even when
such a resin is used, the image cracking portion is reduced to
about 3 to 5% by the image-cracking-inhibiting effect in the case
where the surface tension of the resin-containing liquid was made
higher than that of the coloring pigment ink as found in Examples 1
to 4. In addition, it was known that when the hot air drying is
conducted, an effect to reduce the image cracking to about 0 to 3%
is exhibited. The reason for this is considered to be principally
attributable to the action that evaporation of water in the
resin-containing liquid whose permeation is delayed is accelerated
to accelerate the solidification of the resin-containing liquid,
and so the amount of the resin-containing liquid which contributes
to the permeation can be more reduced compared with the natural
drying.
[0160] Image Formation According to Transfer Type Ink Jet Recording
Method
[0161] An image was formed by using the transfer type ink jet image
forming apparatus illustrated in FIG. 4. The following was used as
a transfer member which is a first recording medium.
[0162] The transfer member was a two-layer structure formed by a
support member and a surface layer member. In this structure, a
flat plate formed of an aluminum alloy was used as the support
member of the transfer member from the viewpoint of required
characteristics such as stiffness capable of withstanding a
pressure upon transfer and dimensional accuracy. As the surface
layer member of the transfer member, a siloxane compound surface
layer was formed according to the following method using a
hydrolyzable organic silicon compound as a raw material.
Glycidoxypropyltriethoxysilane and methyltriethoxysilane were mixed
at a molar ratio of 1:1, and refluxing under heat was conducted for
24 hours or more in an aqueous medium by using hydrochloric acid as
a catalyst to obtain a hydrolyzable condensate solution. The
hydrolyzable condensate solution was diluted to 10 to 20% by mass
with methyl isobutyl ketone, and a photocationic polymerization
initiator (SP150, product of Adeka Corporation) was added in an
amount of 5% by mass with respect to the solid content to obtain a
desired coating solution. The coating solution of the above
composition was used to form a film on the support member by spin
coating. As a pretreatment of the support member, a plasma
treatment was conducted on the surface thereof to improve its
coatability and adhesion to a surface layer. The thus-formed film
was then irradiated with light from a UV lamp, exposed and heated
for 3 hours at 130.degree. C. to obtain a cured product. The film
thickness of the surface layer by the cured product at this time
was 0.3 .mu.m.
[0163] In addition, the above coat paper (MIRROR COAT G, ream
weight: 127.9 g/m.sup.2, product of Oji Paper Co., Ltd.) was used
as a second recording medium.
[0164] A liquid ejection device for a pigment ink, a liquid
ejection device for a resin-containing liquid and ejection amounts
of the pigment ink and the resin-containing liquid were set to the
same conditions as in Examples of the above-described direct
drawing type ink jet image forming apparatus.
[0165] In this example, a case where four ejections are performed
on a region 600 dpi long and 600 dpi wide was defined as 100% duty.
After the reaction liquid was applied to the transfer member, a
solid image of 200% duty or 300% duty was formed with the pigment
ink, and the resin-containing liquid was then ejected at 200% duty
on the image, thereby forming a bright image having high glossiness
and gloss uniformity. In addition, an interval between the ejection
of the pigment ink and the ejection of the resin-containing liquid
was set to 100 ms.
[0166] Examples and Comparative Example of the present invention
will hereinafter be described.
Examples 2-1 to 2-4 and Comparative Example 2-1
[0167] Each of the resin-containing liquids shown in Table 1 was
used as the resin-containing liquid to form a bright image by image
formation according to the above-described transfer type ink jet
recording method. The drying method after the formation of the
bright image is shown in Table 7. Incidentally, the natural drying
is a drying method in which the image is left to stand without
using a hot air drying device.
[0168] Evaluation of Image-Cracking-Inhibiting Effect
[0169] Image formation was conducted according to the conditions of
respective Examples and Comparative Example to evaluate the degrees
of image cracking occurred at that time in the same manner as in
Example 1-1. The criterion of the evaluation is as shown in the
following Table 6.
TABLE-US-00006 TABLE 6 Proportion of image cracking portion
Evaluation 0% or more and less than 2% A 2% or more and less than
3% B 3% or more and less than 5% C 5% or more and less than 15% D
15% or more E
[0170] Results obtained by comparing the degrees of the image
cracking by using the above-described quantitative method are shown
in Table 7.
TABLE-US-00007 TABLE 7 Degree of image Resin-containing liquid
Drying method cracking Ex. 2-1 3 Natural drying C Ex. 2-2 10
Natural drying C Ex. 2-3 11 Natural drying B Ex. 2-4 12 Natural
drying A Comp. 1 Natural drying D Ex. 2-1
Example 2-5
Evaluation of Glossiness and Gloss Uniformity
[0171] An image obtained by conducting printing on coat paper
(MIRROR COAT G, product of Oji Paper Co., Ltd.) at 200% duty or
300% duty with the above-described pigment ink by means of the
transfer type ink jet image forming apparatus used in Example 2-1
and then ejecting Resin-containing liquid 3, and an image obtained
by conducting only the printing at 200% duty or 300% duty with the
pigment ink were subjected to glossiness measurement. The
evaluation method is the same as in Example 1-10. Evaluation
results are shown in Table 8.
TABLE-US-00008 TABLE 8 Evaluation result according to Kind of image
according to recording conditions GB1 value Image obtained by
ejecting Resin-containing A liquid 3 at 200% duty on 200% duty
image by pigment ink Image obtained by ejecting Resin-containing A
liquid 3 at 200% duty on 300% duty image by pigment ink Image
obtained by conducting only the printing C at 200% duty by pigment
ink Image obtained by conducting only the printing B at 300% duty
by pigment ink
[0172] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0173] This application claims the benefit of Japanese Patent
Application No. 2015-089105, filed Apr. 24, 2015, which is hereby
incorporated by reference herein in its entirety.
* * * * *